a. Field of the Invention
The present invention relates generally to insoles for footwear, and, more particularly, to a contoured insole having a soft cushioning upper blank and a rigid reinforcement cap which extends around the heel end of the blank so as to provide support at predetermined areas of the insole.
b. Background Art
Cushioning insoles of various types are known for use in shoes, particularly for use in running shoes and other shoes intended for athletic activities. Typically, these insoles take the form of a relatively thin layer of foam material which rests atop the sole of the shoe, and are often removable for washing or replacement.
While commonly used, conventional insoles of this general type have proven less than ideal in several respects. Firstly, the top surface of the foam material is often given a pronounced contour in an effort to support and cradle the wearer""s foot, but because the foam is intended mainly to cushion the foot, it typically lacks sufficient strength and firmness to simultaneously provide the necessary support for proper biomechanical function of the foot, particularly in the rearfoot and arch areas. This problem is aggravated by the fact that most athletic shoes are xe2x80x9csoft sidedxe2x80x9d to a greater or lesser extent, i.e., the uppers are formed of cloth, vinyl, or other flexible materials which yield outwardly under pressure, thereby providing very little inward buttressing around the insole. As a result, conventional contoured insoles tend to deform and xe2x80x9cmushxe2x80x9d downwardly and outwardly under the foot without providing any meaningful level of support, and also tend to break down and lose their shape very rapidly in use.
Some efforts have been made to correct these problems by including higher durometer materials in one or more areas of the device. For example some cushioning insoles have been constructed with a band of heavier durometer rubber or similar material added in the arch area and around the heel of the foam footbed. However, these materials has done little if anything to increase the strength or durability of the insoles, and they have not had the strength or configuration necessary to provide proper support for the wearer""s foot.
One form of device which does offer a high degree of durability and support is that which is disclosed in U.S. Pat. No. 4,597,196. This device includes a full-length resilient blank formed of rubber or similar material, with a resilient pad extending longitudinally down the bottom of the blank and a somewhat horseshoe-shaped moldable cork member extending along the sides and around the heel area. The assembly also includes a fairly rigid plastic cap which fits over the bottom of the device and extends partway up the rearfoot sides. However, while highly successful for its intended purposes, this device is principally a custom-molded, multi-component unit, and is consequently comparatively expensive and specialized in nature. Moreover, it is a fairly heavy device, and the added weight may not be desirable in many circumstances, particularly for use in certain athletic shoes.
In short, the construction which is shown in the ""196 patent provides a somewhat xe2x80x9chigh endxe2x80x9d, specialized product, which is not particularly well suited to the low cost, high volume athletic shoe market.
Accordingly, there exists a need for a lightweight, low-cost contoured insole which provides effective cushioning for a foot, yet which is nevertheless durable and longlasting in use. Furthermore, there exists a need for such an insole which provides proper support in the heel and rearfoot areas so as to optimize the biomechanical motions of the foot.
The present invention has solved the problems cited above, and is an insole assembly for a shoe or other article of footwear. Broadly, the insole comprises: (a) a substantially soft, resiliently compressible cushioning blank member having an upper surface for engaging a plantar surface of a foot and a bottom surface for engaging a sole of a shoe; and (b) a substantially rigid, resiliently flexible cap member mounted to the blank member, the cap member comprising: an upstanding wall portion which extends in supporting engagement with an outer surface of the blank member around a rearfoot end and along medial and lateral sides thereof, and at least one generally horizontal flange portion which extends inwardly from the wall portion of the cap member in supporting engagement with a bottom surface of the blank member so as to provide additional rigidity and support to the blank member beneath a selected area of the wearer""s foot.
The cushioning blank member may comprise a downwardly concave heel cup portion for engaging a heel of the wearer""s foot, and an upwardly arched midfoot portion for engaging an arch portion of the foot. The flange portion of the cap member may comprise first and second primary flanges which extend inwardly across the bottom surface of the blank member under the arched midfoot portion thereof, the flanges having inner edges which are spaced apart from one another by a portion of the bottom surface of the blank member. The inner edges of the flanges may follow generally arcuate paths between forward and rearward end points which are located proximate the wall portion of the cap member.
The rearward end points of the flanges may be positioned proximate a forward end of the heel cup portion of the blank member. The flange portion of the cap member may further comprise a horseshoe-shaped rearfoot flange which extends around the rearfoot end of the blank member so as to connect the rearward end points of the primary flanges.
The flange portion of the cap member may further comprise first and second secondary flanges positioned forwardly of the primary flanges. The secondary flanges may have inner edges which are spaced apart from one another by a portion of the open area of the blank member which is wider than that by which the edges of the primary flanges are spaced apart. The inner edges of the secondary flanges may also follow generally arcuate paths between rearward and forward end points which are located proximate the wall portion of the cap member, and the rearward end points of the secondary flanges may coincide with the forward end points of the primary flanges.
The forward end points of the flanges on the medial side of the blank member may be positioned longitudinally forward of the corresponding end points on the lateral side, so that the forward end points define a series of borders of between distinct areas of support between the flanges, which borders extend at rearward angles from the medial side to the lateral side of the blank member. The angles at which the borders extend may be generally parallel to an angle at which the metatarsal heads of a wearer""s foot extend, from a medial side to a lateral side thereof.
The present invention also provides a shoe or other article of footwear having an insole assembly generally as described above.
The invention, together with further aspects and advantages thereof, will be further understood by reference to the following detailed description and accompanying drawings.